In the lithographic printing process, a lithographic plate comprising an aluminum sheet is initially coated with a photosensitive layer. A negative is applied over the photosensitive layer, after which the lithographic plate having the negative applied thereto is exposed to high intensity light. The negative is then removed, and the plate is fed into a lithographic plate processor.
In the processor, developer is initially applied to the exposed surface of the plate and is then spread across the entire exposed surface. A developer apparatus distributes the developer on the exposed surface. Next, the exposed surface is washed to remove excess developer. A layer of gum arabic is then applied to the exposed surface, after which the lithographic plate may be dried.
Following the processing operation, the lithographic plate is ready for use in a conventional lithographic press to effect printing. In the press, ink is applied to the plate by means of a roller. The plate is then utilized to print on a blanket, which is in turn used to print a plurality of sheets formed from paper or other material in a conventional manner.
U.S. Pat. No. 3,936,853, issued Feb. 3, 1976 to Milam E. Mart discloses one such developer apparatus. In that patent, spreader members are rotated about axes of rotation along a line extending transversely to the direction of movement of the lithographic plate through the processor. Both developer and gum arabic are applied on the lithographic plate through a conduit having a plurality of discharge outlets.